Do Relatives With Greater Reproductive Potential Get Help First?: A Test of the Inclusive Fitness Explanation of Kin Altruism

Do Relatives With Greater Reproductive Potential Get Help First?: A Test of the Inclusive Fitness Explanation of Kin Altruism. Jordan Schriver et al. Evolutionary Psychology, August 8, 2019. https://doi.org/10.1177/1474704919867094

Abstract: According to inclusive fitness theory, people are more willing to help those they are genetically related to because relatives share a kin altruism gene and are able to pass it along. We tested this theory by examining the effect of reproductive potential on altruism. Participants read hypothetical scenarios and chose between cousins (Studies 1 and 2) and cousins and friends (Study 3) to help with mundane chores or a life-or-death rescue. In life-or-death situations, participants were more willing to help a cousin preparing to conceive rather than adopt a child (Study 1) and a cousin with high rather than low chance of reproducing (Studies 2 and 3). Patterns in the mundane condition were less consistent. Emotional closeness also contributed to helping intentions (Studies 1 and 2). By experimentally manipulating reproductive potential while controlling for genetic relatedness and emotional closeness, we provide a demonstration of the direct causal effects of reproductive potential on helping intentions, supporting the inclusive fitness explanation of kin altruism.

Keywords: altruism, inclusive fitness, reproduction, emotional closeness, family relationships